For the analysis of biological, medical or chemical samples, smear samples are also used besides liquid samples, for example blood samples. In this case, for example, a sterile cotton swab is wiped over a body site to be analyzed, for example the oral mucosa, so that a part of the desired sample material remains adhering to the cotton swab or partially impregnates it. In forensic molecular biology, for example, saliva samples are often taken in the form of smears in order to identify a culprit through a DNA analysis.
In order to make the smear sample placed on the cotton swab or a comparable sample carrier available for further analysis, extraction of the smear sample from the sample carrier is necessary. In known methods, this has previously been done manually. In the case of a cotton swab, for example, a stick carrying the cotton bud is broken off close to the cotton bud for this purpose. To this end, there is generally a weakened fracture site on the stick. The cotton bud is subsequently put into a vessel such as an Eppendorf tube filled with a carrier liquid, for example a salt solution, shaken (“vortexed”) and centrifuged at a high speed. In this way, the smear sample is released from the cotton bud and is available dissolved or suspended in the carrier liquid. By means of this carrier liquid, it can be delivered for further processing and thereby analyzed.
US 2003/0129767 A1 discloses a test unit in which a cotton stick with a smear sample can be introduced into a container. After supplying a solution liquid, the container is introduced into a test strip so that the dissolved smear sample can enter inside the test unit. The smear sample mixed with reagents is transported by capillary forces into a detection zone, on which the result of the test can be read.
Biochips are increasingly gaining importance for the analysis of samples. Using biochips, for example, it is possible to detect the concentration or presence of biomolecules, for example nucleic acid fragments or proteins, in biological or medical samples. Biochip systems are based, for example, on a multicomponent system in which the biochip itself is arranged in a single-use unit (cartridge). The cartridge is inserted into a reader and controller in order to carry out the analysis. The reagents needed for carrying out the analysis may be stored in the cartridge in a dry or liquid form or in the reader.
If smear samples are intended to be processed using such biochip systems, then manual release as described above is necessary since in many biochip systems only liquid samples can be processed directly. This is an impediment to the otherwise of fully integrated analysis opportunity offered by biochips.